Pil Hyung Lee (Department of Cardiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea) and others report that successful percutaneous coronary intervention (PCI) of a native chronic total occlusion lesion is not associated with improved long-term survival compared with a failed procedure. However, successful procedures are associated with significantly less target vessel revascularisation and coronary artery bypass grafting (CABG).
Writing in JACC: Cardiovascular Interventions, Lee et al report that procedural success rates of PCI in chronic total occlusions “have dramatically improved” in recent years because of improvements in operator experience and the development dedicated devices and techniques. They add that the introduction of drug-eluting stents (and the associated reduction in restenosis and repeat revascularisations) has given interventional cardiologists “the advantage of performing PCI for more complex coronary chronic total occlusions”. However, the authors comment that survival data for successful PCI of chronic total occlusions with current standards of practice (eg. drug-eluting stents) are sparse. Therefore, they write: “The aim of our study was to evaluate the impact of successful revascularisation of native chronic total occlusions using drug-eluting stents on the long-term clinical outcomes as compared with failed chronic total occlusion PCI.”
Reviewing data for patients who underwent PCI for chronic total occlusions at their centre (Asan Medical Center) between 2003 and 2014, Lee et al identified 1,004 patients (1,021 chronic total occlusion lesions) in whom PCI with drug-eluting stents was successful and 169 patients in whom PCI was not successful. Of those who underwent successful PCI, 463 received a first-generation drug-eluting stent and the remainder (541) received a newer-generation drug-eluting stent.
The primary safety endpoints were the rates of all-cause mortality and a composite of all-cause death or Q-wave myocardial infarction. The primary efficacy endpoints were rates of target vessel revascularisation and CABG.
After a median follow-up of 4.6 years, there were no significant differences in the primary safety endpoints between groups. The rate of all-cause mortality was 8% for the successful PCI patients vs. 7.1% for the failed PCI patients (p=0.83) and the composite rate of death or Q-wave myocardial infarction was 9% vs. 8.5%, respectively (p=0.94).
According to Lee et al, this finding contradicts those of previous studies of successful PCI of chronic total occlusions. They comment: “One plausible explanation for this finding is that the revascularisation strategy for non-chronic total occlusion vessel may have affected the clinical outcome.” The authors explain that patent non-chronic total occlusion vessels may have had a prognostic impact “via maintenance of myocardial perfusion at both non-chronic total occlusions and chronic total occlusion artery-related territories.”
Furthermore, Lee et al note that the high rate of patients who underwent CABG after failed PCI (16.7%) may have also affected the outcome, reporting: “Analysis excluding patients who underwent subsequent CABG demonstrated the risk of death for patients with successful PCI to be decreased by 18% compared with the original result.”
However, successful PCI was associated with significant lower rates of target vessel revascularisation (4.4% vs. 20.9%; p<0.001) and CABG (0.4% vs. 16.7%; p<0.001). The authors comment while the adjusted risk of all-cause mortality and the composite of death or Q-wave myocardial infarction remained comparable between the groups, the adjusted risk of target vessel revascularisation and CABG was significantly higher in patients with failed PCI.
Concluding, Lee et al state that the “true beneficial effect” of successful chronic total occlusion PCI cannot be made by comparing the outcomes of successful PCI with those of failed PCI. They add that a randomised comparison between chronic total occlusion PCI and optimal medical therapy is needed to determine the true beneficial effect and that the ongoing DECISION-CTO (Drug-eluting stent implantation vs. optimal medical treatment in patients with chronic total occlusion) trial aims “to resolve this long-standing open question.”